U.S. patent number 9,662,123 [Application Number 14/448,490] was granted by the patent office on 2017-05-30 for vertical cutter and method of use.
This patent grant is currently assigned to Amendia, Inc.. The grantee listed for this patent is Kenneth Richard Barra, William Carlton Tally. Invention is credited to Kenneth Richard Barra, William Carlton Tally.
United States Patent |
9,662,123 |
Tally , et al. |
May 30, 2017 |
Vertical cutter and method of use
Abstract
A detachable vertical cutter for insertion into a cylinder or
tube is formed as a single unitary structure. The single blade has
a pair of tool attachment end portions and a cutting blade
extending in a loop between the attachment ends. The cutting blade
is inclined vertically relative to a longitudinal axis of a
cylinder or tube into which the attachment ends can slide into. The
cutting blade has a cutting edge, a portion of which when extended
free of the cylinder or tube will extend a distance greater than
the tube outside diameter. The cutting edge when pushed inwardly
and pulled outwardly between adjacent vertebrae scrapes and cuts
disc material. When retracted the cutting blade deflects into the
cylinder or tube for insertion or extraction into or from the disc
space.
Inventors: |
Tally; William Carlton (Athens,
GA), Barra; Kenneth Richard (Acworth, GA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Tally; William Carlton
Barra; Kenneth Richard |
Athens
Acworth |
GA
GA |
US
US |
|
|
Assignee: |
Amendia, Inc. (Marietta,
GA)
|
Family
ID: |
55178813 |
Appl.
No.: |
14/448,490 |
Filed: |
July 31, 2014 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20160030060 A1 |
Feb 4, 2016 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
17/1617 (20130101); A61B 17/320016 (20130101); A61B
17/1659 (20130101); A61F 2/44 (20130101); A61B
17/320708 (20130101); A61F 2/4675 (20130101); A61B
17/1671 (20130101); A61B 2017/00473 (20130101); A61B
2017/320008 (20130101); A61B 2017/00867 (20130101); A61F
2/4611 (20130101); A61B 2017/00261 (20130101) |
Current International
Class: |
A61B
17/32 (20060101); A61B 17/16 (20060101); A61F
2/46 (20060101); A61F 2/44 (20060101); A61B
17/00 (20060101); A61B 17/3207 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bates; David
Attorney, Agent or Firm: King; David L.
Claims
What is claimed is:
1. A vertical cutting tool comprises: a shaft to which a cutting
blade can be attached at one end and externally threaded at an
opposite end; a hollow tube or cylinder for receiving the shaft
internally; a rotatable knob affixed to the hollow tube and
rotatable independent of the tube or cylinder, the knob having
internal threads to engage the threads of the shaft; a single
detachable vertical cutter having a pair of tool attachment end
portions and a cutting blade extending in a loop between the
attachment ends; and wherein the cutting blade is inclined
vertically relative to a longitudinal axis of a cylinder or tube
into which the attachment ends slide into, the cutting blade having
a cutting edge, a portion of which when extended free of the
cylinder or tube extends a distance above the tube outside
diameter, the cutting edge cuts linearly relative to the
longitudinal axis as the cutting blade is moved inwardly and
outwardly and when positioned between adjacent vertebrae is
configured to cut disc material by pushing inwardly and pulling
outwardly relative to the disc as the cutting edge of the cutting
blade scrapes and cuts the disc material parallel to the
longitudinal axis of the cylinder or tube, and the cutting blade
when retracted deflects into the cylinder or tube for insertion or
extraction into or from the disc space.
2. The vertical cutting tool of claim 1 wherein the blade is cut
from a flat sheet of shaped memory alloy and heat set to form the
loop.
3. The vertical cutting tool of claim 2 wherein the sheet has a
nominal thickness of 0.5 mm or greater.
4. The vertical cutting tool of claim 3 wherein the cutting blade
has a nominal width of 2.0 mm or greater.
5. The vertical cutting tool of claim 3 wherein the cutting edges
are the inclined outer edges at the intersection of the thickness
and the width.
6. The vertical cutting tool of claim 1 wherein the cutting blade
has curved opposite side spanning a nominal maximum between
opposite sides distance of 10.5 mm or greater.
7. The vertical cutting tool of claim 6 wherein the cutting blade
when withdrawn into the tube or cylinder bends or deflects the
curved sides of the loop to fit the inside diameter as well as
lowering or bending the flattened end vertical inclination to slide
into the tube or cylinder.
8. The vertical cutting tool of claim 6 wherein the cutting blade
has flattened distal end portion between the two curved sides along
a vertical cutting peak extending at least 3 mm.
9. The vertical cutting tool of claim 8 wherein the cutting blade
is configured to fit into a 7 mm to less than 10 mm tube or
cylinder having a nominal outside diameter of 8 mm to 11 mm.
10. The vertical cutting tool of claim 9 wherein the vertical
inclination extends at least 3 mm or greater above the outside
diameter of the tube when the cutting blade is extended free of the
tube.
11. The vertical cutting tool of claim 1 further comprises a push
pull knob fixed to the rotatable knob to move the shaft to which
the cutting blade is attached as the cutting blade cuts linearly
inwardly and outwardly parallel to the tube or cylinder
longitudinal axis.
Description
TECHNICAL FIELD
The present invention relates to an improved tissue and bone
surface scraping and cutting device for preparation of the spinal
disc space for implantation of a fusion implant device.
BACKGROUND OF THE INVENTION
In open spinal vertebrae surgical procedures, the surgeon makes an
incision through the skin and muscle tissue and exposes the area to
be worked on using retractors separating the tissue above the
adjacent vertebral bodies and the interposed disc. Using cutting
devices such as a spoon curette or rongeur, the surgeon cuts away
the bone and disc material and prepares a space for a spinal fusion
device to be placed.
In minimal invasive surgery, the large incision is not used and in
its place a smaller cut is made just large enough to position a
small hollow tube or cylinder into the disc space between the two
vertebrae to be fused together. It is through this tube that the
cutting tools must pass to remove the disc material and prepare the
space for a fusion implant device. The vast majority of these
cutting devices operate by rotational cutting of the tissue to be
removed. This allows for a circular cross sectional removal of the
disc, but requires rather difficult angulation to flatten or widen
the space being prepared. A secondary issue is to flex into a tube
fitting compressed size; the blades typically have two or more
separate cutting blades as in U.S. Pat. No. 5,709,697. This enables
the blades to deflect into a tube, but uses a small pointy tip
prone to break when in use leaving metal fragments.
Very importantly, these rotational devices are limited in vertical
reach that can be achieved. In some small patients, this represents
little trouble, but in larger boned patients, the vertical space
required for the implant can exceed the capacity of the device.
The present invention as described hereinafter avoids these issues
in a new and improved way to provide the surgeon a much simpler and
efficient way to prepare the disc space for implantation.
SUMMARY OF THE INVENTION
A vertical cutter for insertion into a cylinder or tube is formed
as a single unitary structure. The single blade has a pair of tool
attachment end portions and a cutting blade extending in a loop
between the attachment ends. The cutting blade is inclined
vertically relative to a longitudinal axis of a cylinder or tube
into which the attachment ends can slide into. The cutting blade
has a cutting edge, a portion of which when extended free of the
cylinder or tube will extend a distance greater than the tube
outside diameter. The cutting edge when pushed inwardly and pulled
outwardly between adjacent vertebrae scrapes and cuts disc
material. When retracted the cutting blade deflects into the
cylinder or tube for insertion or extraction into or from the disc
space.
The blade is cut from a flat sheet of shaped memory alloy and heat
set to form the loop. The sheet has a nominal thickness of 0.5 mm
or greater. The cutting blade has a nominal width of 2.0 mm or
greater. The cutting edges are the inclined outer edges at the
intersection of the thickness and the width. The cutting blade has
curved opposing sides spanning a nominal maximum width between
opposite sides a distance of 10.5 mm or greater.
The cutting blade when withdrawn into the tube or cylinder bends or
deflects the curved opposing sides of the cutting blade to fit the
inside diameter. This also lowers or bends the flattened end
vertical inclination to slide into the tube or cylinder. The
cutting blade has flattened distal end portion between the two
curved sides along a vertical cutting peak extending at least 3 mm.
The cutting blade is configured to fit into a tube or cylinder
having a nominal outside diameter of 8 mm. The vertical inclination
of the cutting blade extends at least 2 mm or greater above the
outside diameter of the tube when the cutting blade is extended
free of the tube.
A vertical cutting tool has a shaft, a tube or cylinder and a
single cutting blade. The shaft has the cutting blade attached at
one end and is externally threaded at an opposite end. This hollow
tube or cylinder is for receiving the shaft internally. A rotatable
knot is affixed to the hollow tube and is rotatable independent of
the tube or cylinder. The knob has internal threads to engage the
threads of the shaft. This rotatable knob adjusts the protruding
amount to deploy the cutting blade. The single vertical cutter has
a pair of tool attachment end portions and a cutting blade
extending in a loop between the attachment ends. The cutting blade
is inclined vertically relative to a longitudinal axis of a
cylinder or tube into which the attachment ends slide into. The
cutting blade has a cutting edge, a portion of which when extended
free of the cylinder or tube extends a distance above the tube
outside diameter. The cutting edge when pushed inwardly and pulled
outwardly scrapes and cuts the disc material, and when retracted
deflects into the cylinder or tube for insertion or extraction into
or from the disc space. The vertical cutting tool further comprises
a push pull knob fixed to the rotatable knob to cut inwardly and
outwardly parallel to the tube or cylinder longitudinal axis.
The vertical cutter of the present invention allows for the method
of preparing a void space between adjacent vertebrae for placing a
fusion implant device comprises the steps of locating a position on
the patient to make an incision; cutting the tissue at the location
by making a small incision; placing an outer guide tube having an
inside diameter into the incision; inserting a cutting tool with a
retracted cutting blade inside a tube sized to pass through the
inside diameter of the guide tube while having the cutter stowed
internally; extending the tool tube past the guide tube directed
toward a disc space; protracting the cutting blade free of the tool
tube while orienting the cutting blade vertically up or down
relative to a longitudinal axis of the tool tube and wherein the
protracted cutting blade has a loop shape with an inclined cutting
edge extending several mm above or below the tube; cutting away
disc tissue directed at one vertebrae to form a void space by
pushing and pulling the tool in an axial direction; scraping the
cutting blade along the exposed bone surfaces of the adjacent
vertebrae thereby removing an outer layer or layers of bone tissue
and laterally inclining the guide tool left or right slightly to
widen the void space; turning the tool 180 degrees to repeat the
steps of cutting away disc tissue and scraping bone layers of the
other vertebra to complete the void space; and retracting the
cutting blade and withdrawing the cutting tool.
The method can further include a step of retracting the cutting
blade prior to turning the tool 180 degrees. The method wherein the
cutting edge has a flat portion extending at least 3 mm above the
tool tube and the tool tube has an outside diameter of 8 mm. The
method wherein the cutting edge can cut disc tissue and vertebral
bone to form a total maximum void space height over 14 mm, 7 mm
upwardly and 7 mm downwardly between two adjacent vertebrae. The
method wherein the cutting blade can be partially refracted to cut
at lower heights.
DEFINITIONS
As used herein and in the claims:
A "curette" is a surgical instrument designed for scraping or
debriding biological tissue or debris in a biopsy, excision, or
cleaning procedure. In form, the curette is a small hand tool,
often similar in shape to a stylus; at the tip of the curette is a
small scoop, hook, or gouge.
A "rongeur" is a strongly constructed instrument with a
sharp-edged, scoop-shaped tip, used for gouging out bone.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described by way of example and with
reference to the accompanying drawings in which:
FIG. 1 is a perspective view of the cutter tool assembly of the
present invention.
FIG. 1A is an exploded view of the tool assembly of FIG. 1.
FIG. 2A is a plan view of the tooling tube.
FIG. 2B is side plan view of the internal shaft.
FIG. 3 is a plan side view illustrating the rotatable retraction
and protraction knob for moving the cutter blade of the cutting
tool into and out of the tooling tube.
FIG. 4 is a perspective view of the cutting blade of the present
invention as formed.
FIG. 4A is a plan view of the cutting blade, the dashed lines
representing the sheet from which the cutting blade can be
formed.
FIG. 4B is a top view of the cutting blade as formed.
FIG. 4C is a partial view taken along lines A-A of FIG. 4B showing
one portion of the cutting blade, the opposite portion having been
removed.
FIG. 4D is an end view of the cutting blade illustrating the
vertical elevation of the cutting blade relative to the attachment
portions.
FIG. 5 is a perspective view showing the cutting blade protracted
and extending outward from the tooling tube.
FIG. 6 is a side perspective view showing the cutting blade
protracted relative to the tooling tube.
FIG. 7 is a side view showing a portion of the cutting blade with
dimensions from the attachment knob to the vertical elevation above
the attachment means.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIGS. 1 and 1A, the cutting tool device 100 of
the present invention is illustrated. The device 100 includes a
detachable vertical cutter 10, a tool tube 102, a rotatable
retraction and protraction knob 120 and a push pull knob 130 to
provide linear cutting capability as the tool 100 is pushed and
pulled inward between two vertebral bodies to remove disc tissue
and to scrape the bone exposed end plate surfaces.
With reference to FIG. 1A, further illustrated internal to the tool
tube 102 is a shaft 112. The shaft 112 provides a way to attach the
vertical cutter 10. As further illustrated in FIG. 2A, the tube 102
has a "T" shaped end 104 that is adapted to fit in the rotatable
knob 120 as illustrated in FIG. 3. The "T" shaped end 104 has a
knob 120 mounted thereabout so that the knob 120 can rotate without
rotating the tube 102. The knob 120 has internal threads 122
adapted to engage the threads 110 of the shaft 112 as illustrated
in FIG. 2B. The combination of threads 110, 122 are designed so the
shaft can be pulled or pushed axially along the longitudinal axis
of the tool by the rotation of the knob 120 best illustrated in
FIG. 3. A slot is provided in the tool in FIG. 3 exposing the
threads 110 of the shaft 112. The threads 110 can be moved between
positions 105 and 103 or further if so desired. This open window
106 provides a means for the surgeon to see the amount of travel
that the vertical cutter 10 is making relative to the tool tube 102
when it is positioned inside the vertebral bodies. The shaft 112
has a flat end 116 to which the knob 130 is fixed.
With particular reference to the detachable vertical cutter 10, as
illustrated in FIGS. 4 through 7, the vertical cutter 10 has
attachment ends 12 and 14 with an opening 11 that will conveniently
fit on the attachment location 114 of the shaft 112. The openings
11 are oriented at 90 degrees to attachment locations 114. The
attachment locations 114 are positioned on each side of the shaft
112 such that when the vertical cutter 10 is mounted on the
attachment shaft 112 and pulled inside the tube 102 it securely
holds the vertical cutter 10 in position so that it can be pulled
internally within the tube 102. As illustrated in FIG. 4A, the
vertical cutter 10 was formed as a single piece, preferably of
shaped memory alloy material such as Nitinol wherein the material
was cut from a blank sheet approximately 0.5 mm thick. The blank
sheet is illustrated by dashed lines in FIG. 4A. As shown, the
attachment ends 12 and 14 are at the extremes of this sheet where
the cutting blade 20 is interposed between the attachment ends 12,
14. As shown, the width W.sub.B is approximately 2 mm in the
exemplary embodiment. Punched through the attachment ends 12, 14
are the attachment holes 11 as illustrated. The cutting blade width
W.sub.B is substantially uniform across the cutting blade 20,
however may be slightly narrower at a flat portion 25. The flat
portion 25 extends about 3 mm in length. When the shaped memory
alloy material is formed into the desired cutting blade shape which
is of a general oval nature as illustrated in the top view of FIG.
4B, the flat portion 25 will be at the very peak of the vertically
inclined cutting blade 20. As shown, the cutting blade sides 22 and
24 are inclined relative to the attachment ends 12, 14 and are
offset slightly lower than the center line of the attachment ends
12, 14. This enables the cutting blade 20 when bent in the
configuration shown in FIG. 4B to take the shape as illustrated.
The cutting blade sides 22, 24 extend widthwise a distance W.sub.T
of approximately 10.5 mm in this exemplary embodiment to form a
large oval with a flat top.
As illustrated in FIG. 4C, the blade side portion 22 on the
attachment end 12 is shown, the other side of the cutting blade 20
has the end portion 24 and 14 (not illustrated) similarly inclined.
An acute angle is shown of approximately .theta. relative to a
horizontal plane which can be varied dependent on the length and
the amount of height required. However, it is believed important
that the angle .theta. be less than 45 degrees preferably less than
30 degrees as illustrated.
With reference to FIG. 4D, the cutting blade portion 20 has the
sides 24 and 22 shown inclined to the flat portion 25 inclined and
raised upward relative to the attachment ends 12, 14 to the flat
portion 25. Again, as previously mentioned, the width of the
cutting blade 20 is of substantially uniform thickness W.sub.B of
about 2 mm and has a cutting edge that is also generally uniform in
thickness of 0.5 mm or less. This provides a substantially strong
and yet flexible blade 20 such that it can be retracted and pulled
inside the tube 102. This attachment of the vertical cutter 10 is
illustrated in FIG. 5 where the thickness of the blade 20 is
illustrated as dimension t. In the exemplary vertical cutter 10, t
was about 0.5 mm.
With reference to FIG. 6, the vertical cutter 10 is also shown in
the protracted position where it is free of the tool tube 102. The
tool tube 102 has an outside diameter OD of approximately 8 mm in
this exemplary embodiment with an inside diameter of 6.85 mm. The
width of the attachment ends 12, 14 is slightly less than the 6.85
mm such that they can slide inwardly to be attached to the shaft
112 at the attachment locations 114. The vertical cutter 10, when
attached, has a vertical distance from the axis of rotation, this
is called the cutting travel distance CT or cutting travel from the
axis and it approximately 7.3 mm in the exemplary embodiment. This
means that the cutting blade 20 extends above the outside diameter
of the tool tube 102 by a distance of approximately 3.3 mm. It is
important to note that this distance CV extending vertically above
or below the tube 102 on an inclination, as shown, is achieved when
the cutting blade 20 is free from the tube 102. As shown, the
cutting blade 20 will extend vertically upward relative to the axis
in such a fashion that the flat end 25 cutting edge can reach a
maximum level of 7.3 mm in height to the vertebrae surface above
it. This allows the cutting blade 20 to cut not only into the disc
material, both the nucleus pulposus and the annulus fibrosus, but
also to be able to scrape along the interior surface of the
vertebral plate. The vertebral plate must be remembered to be
somewhat of a saucer shape turned upside down wherein the edges
conform inwardly slightly while the inner portion of the vertebral
plate is raised in a flattened elevated dome shape. This is
important in that the cutting blade 20 is designed to be able to
scrape not only the disc material, but also the thin layers of this
end plate of the vertebral body. By scraping it, microfractures
occur and improved bone surface preparation can be achieved for a
fusion implant device. As shown, the flat portion 25 has a width of
approximately 3 mm or greater. This enables the device to be pushed
and pulled into and out of the disc space without any rotational
cutting. All cutting is achieved by linear action and to widen this
void space required for the implant it is important to remember
that one simply can grab the outer tube 200 that has been inserted
into a small incision at the direct location and tilt it laterally
slightly left or slightly right on a very small inclination. This
allows the cutting blade 20 to move slightly laterally and
continued pushing and pulling can create a void space approximately
10 to 15 mm for an implant 9 mm wide if so desired. The cutting
blade 20 can be held in a slightly retracted position if lowered
cutting heights are need. So on initial cutting, the cutting blade
20 can be slightly retracted and pushed and pulled to cut some
material away and then continue to be pushed and pulled in a fully
retracted condition due to the flexibility of the cutting blade 20,
it will simply scrape along the bones outer edge removing a thin
layer and also provide a good planar surface to receive the fusion
implant device.
FIG. 7 is a similar view to that of FIG. 6 only showing a side view
and only one portion of the blade 20. It is important to note that
since the cutting blade 20 is made in a looped configuration,
having a somewhat oval shape flattened at the peak, it provides a
substantial amount of width for cutting as the entire cutting edge
21 is on a slight incline meaning that the side surface and the top
of the blade 20 form an angulation such that only the edge 21 of
the cutting surface is doing the primary cutting, therefore there
is no need for a very sharp razor edged blade. This blade 20 will
cut at the edge 21 of the width and thickness performing a scraping
action to remove both the disc material and the layers of bone
material needed to be removed in preparation of the void space.
This cutting tool 100, as illustrated, with the vertical cutter 10
provides a unique way of removing disc material and preparing two
adjacent vertebrae for receiving any spinal fusion implant device.
The surgeon will simply locate a position on the patient's back to
make an end incision. The surgeon cuts the tissue at the location
by making a small incision and inserting a solid tapered dilator to
allow insertion of an outer guide tube 200 that will hold the tool
tube 102 portion of the tool 100. This outer tube 200 is
illustrated in FIG. 7. This tube 200 is then placed into the small
incision in the desired location and inserted partially therein.
This tube 200 will have an outside diameter of approximately 9.2 mm
when using a tool tube 102 having an outside diameter of 8 mm. This
means that the outer tube 200 has an inside diameter of
approximately slightly greater than 8 mm so that the tool tube 102
can slide freely in and out of this outer sheathing or guide tube
200. As illustrated, the surgeon will insert the cutting tool 100
with the retracted vertical cutter 10 inside the tool tube 102
which has been sized to pass through the inside diameter of the
guide tube 200 while having the cutting blade 10 stowed internally.
The surgeon will use the outer tube 200 to space the adjacent
vertebral bodies wherein the disc material is intended to be
removed. This spacing of the vertebrae allows the tool tube 102 to
slide inward to the disc material and extending past the guide tube
200 directly towards or into the disc space. At this point the
surgeon protracts the vertical cutter 10 by rotating the knob 120.
As the cutting blade 20 extends past the tool tube 102 it will be
moved into a free position and the shaped memory alloy cutting
blade 20 will return to its free and unrestrained condition. As
such the blade 20 will then extend above the inner tube by
approximately 3.3 mm as discussed. When this occurs, the surgeon
can then push and pull on the cutting blade 10 creating a void
surface by removing the disc tissue. This includes the nucleus
pulposus and the annulus fibrosus of the disc. Once this is removed
the surgeon can continue to remove disc material by tilting on a
slight lateral angulation, the entire guide tube 200 and tool 100
inside on a very slight angle using a lateral movement. This
increases the width that can be cut such that the flat edge 25 can
create a void space of at least 10 to 15 mm wide to receive the
fusion implant device of 9 mm. Once this has occurred, the surgeon
can continue to scrape on the exposed end plate of the vertebral
body. By doing this, he or she will create cracks and fissures that
will improve the osteoinductivity of the bone material adjacent the
implant. This will accelerate the fusion of the bone implant and
accelerate the healing time.
In order to cut the opposite adjacent vertebral body disc material,
the surgeon can either retract if so desired or simply rotate the
tool 100 such that it lines up with a vertical downward extension
if he has previously cut in a vertical upward position. By
extending the tool 100 in a downward direction he can now cut the
lower vertebral body disc tissue above it and prepare that space by
repeating the procedure in a push pull manner completing all the
cutting without any requirement for rotational cutting of disc
material. In this way, a chamber or void space that is basically
rectilinear and ideally suited for receiving a spinal implant
device is formed. Once all the material has been cut away and the
end plates have been scraped, the device can be retracted and
pulled out of the guide tube 200 such that an implant device can be
positioned through the guide tube 200 to complete the procedure.
While various dimensions have been mentioned for the exemplary
embodiment, these dimensions can be varied using the concepts
taught herein and will still be within the scope of the present
invention.
Variations in the present invention are possible in light of the
description of it provided herein. While certain representative
embodiments and details have been shown for the purpose of
illustrating the subject invention, it will be apparent to those
skilled in this art that various changes and modifications can be
made therein without departing from the scope of the subject
invention. It is, therefore, to be understood that changes can be
made in the particular embodiments described, which will be within
the full intended scope of the invention as defined by the
following appended claims.
* * * * *